The present invention relates to an image sensing apparatus represented by a video camera and, more particularly, to an image sensing apparatus having a function of reading an image from a negative film, a slide film, or the like.
Along with rapid improvements of the techniques of personal computers and their peripheral devices, for example, it has now become easy for an operator to capture and edit a taken picture on a memory in a personal computer, and to create a unique postcard or poster. Under this circumstance, the market demand in this technical field is increasing year by year.
When an image on a picture is input into a personal computer, image information on the picture must be converted into an electrical signal using a video camera or an electronic still video camera. Since pictures on photographic paper sheets have various sizes, it is troublesome for an operator to set the field angle and to determine how to illuminate each picture upon taking the picture using such camera. Also, a large-scale, dedicated image sensing apparatus such as a fixing base of a video camera, or the like is required.
To solve such problems, an adapter for mounting a negative (or positive) film is attached to an image sensing lens of the video camera, and an image projected via the adapter is sensed by the video camera. The sensed image is converted into a video signal, which is recorded on a magnetic tape or a memory in a personal computer, or is output to a monitor. This adapter is called a xe2x80x9cfilm adapterxe2x80x9d (this specification uses this name) or xe2x80x9cfilm carrier holderxe2x80x9d, and a camera system with this adapter is called a photo video camera system or the like.
The film adapter is merely attached to the lens of a camera, and has only a function of allowing the user to mount a film. For this reason, when the film adapter is used, various setup processes are required. For example, image signal processing inside the camera must be switched in correspondence with a negative or positive image. If this setup process is ignored, a negative image is directly displayed on a monitor. Also, the frame of a film must be positioned accurately. If this setup process is neglected, an image on a film frame, which is moving in the adapter, or an image on a frame which is not set at a predetermined position, is displayed.
Hence, when the film adapter is attached to the conventional video camera and images on a negative film are taken as still images, various switch operations for attaining the above-mentioned setup processes (to be referred to as a xe2x80x9cfilm image sensing modexe2x80x9d hereinafter) are required, resulting in meticulous operations.
However, when a switch for detecting attachment of the adapter is arranged on the video camera main body, the number of parts increases and results in a large camera size and high cost, the video camera main body must be drastically modified, and so on. Such problems are the first problems in the conventional camera attached with the film adapter.
On the other hand, some conventional cameras that can set the film image sensing mode often have two modes, i.e., xe2x80x9csequential shot modexe2x80x9d and xe2x80x9csingle shot modexe2x80x9d. With these cameras, the photographer selects one of such image sensing modes in correspondence with his or her purpose at that time. The sequential shot mode has as its principal object to avoid a loss of an image sensing chance when a moving subject is captured as still images. When a still image is taken using the film adapter, the film as a subject completely stands still integrally with the camera, and identical still images are repetitively taken unless the sequential shot mode is canceled. That is, the switching function of the sequential and single shot modes, which function is convenient for the user, requires extra user operations. Such problem is the second problem of the prior art.
Problems posed when the film adapter is attached to the video camera or the like are not limited to those concerning the operability mentioned above.
More specifically, when the film adapter is not attached to a conventional camera that can mount a film adapter (when the camera is not in the film image sensing mode), the camera must be able to optimally take images of a normal subject as a normal video camera (i.e., the one without any film image sensing function), as a matter of course. For this reason, the signal processing circuit of the camera is set to assure a broad dynamic range, which is not so required in the film image sensing mode. That is, signals input to the video camera normally have a large level difference (dynamic range) depending on the subject to be taken, i.e., a film set in the film adapter or a normal subject. In order to execute normal video image sensing prior to the film image sensing mode and to optimally take images of a subject in the normal video image sensing, the dynamic range of the signal processing circuit of the video camera is set to cover a very broad range from a subject in a dark room to a very bright subject such as a seashore under direct sunlight. On the other hand, in the film image sensing mode using the film adapter, since illumination light coming from a backlight serves as a light source, changes in lightness (luminance level) of a subject (film) are very smaller than those in a normal image sensing mode (ranging from a bright seashore to a dark room). If the signal processing circuit is fixedly set in both the film image sensing mode and normal subject image sensing mode that have a large dynamic range difference, the performance of the signal processing circuit cannot be fully used especially in the film image sensing mode.
When images on a film are taken using a camera which sets an A/D converter in this manner, such A/D converter is not suitable for the film image sensing mode with a narrow input dynamic range, and the quality of images to be recorded or displayed on the monitor deteriorates. This is a problem (third problem) arising from circuit setups.
Another problem (fourth problem) arising from circuit setups will be explained below. This problem is posed since the conventional camera that can mount the film adapter has moving image-priority circuit setups.
The conventional camera that can mount the film adapter will be explained below with reference to FIGS. 1 and 2.
Referring to FIG. 1, reference numeral 2001 denotes a film adapter; 2002, a film; 2003, an imaging lens; 2004, an image sensing element for photoelectrically converting incoming light; 2005, a signal processing circuit for generating luminance and chrominance signals based on signals generated by the image sensing element 2004; 2006, a reversing circuit for converting a negative image into a positive image; 2007, a switching circuit for selecting whether or not that negative/positive reversing is to be done; 2008, a noise reduction circuit (N.R.) for reducing noise components in an image signal; and 2009, an encoder circuit for converting the luminance and chrominance signals into a video signal.
The film adapter 2001 has a light source for illuminating the film 2002. Light transmitted through the film 2002 is imaged on the image sensing element 2004 via the lens 2003. An optical signal incident on the image sensing element 2004 is photoelectrically converted, and the signal processing circuit 2005 generates luminance and chrominance signals based on the converted signals. In this case, when the film 2002 to be sensed is a positive film, the outputs from the signal processing circuit 2005 are directly input to the noise reduction circuit 2008 by the switching circuit 2007. On the other hand, when the film 2002 is a negative film, the outputs from the signal processing circuit 2005 are converted into those for a positive image by the reversing circuit 2006, and the converted signals are input to the noise reduction circuit 2008.
FIG. 2 is a block diagram showing the arrangement of the frame correlation noise reduction circuit 2008. In FIG. 2, reference numeral 2031 denotes a frame memory for storing an image signal for at least one frame; 2032 and 2033, multipliers for multiplying a signal by coefficients; and 2034 and 2035, adders for adding signals.
In the circuit shown in FIG. 2, let (Sin)n be the signal input of the n-th frame, (Sout)n be the signal output of the n-th frame, and (Sout)nxe2x88x921 be the signal output of the (nxe2x88x921)-th frame from the frame memory 2031. As shown in equation (1) below, the output (Sout)n is obtained by adding the product of the input (Sin)n and a coefficient k and the product of the output (Sout)xe2x88x921 and a coefficient (1xe2x88x92k):
(Sout)n=kxc2x7(Sin)n+(1xe2x88x92k)xc2x7(Sout)nxe2x88x921(0 less than kxe2x89xa61)xe2x80x83xe2x80x83(1)
Noise components produced between the (nxe2x88x921)-th and n-th frames are reduced by multiplication by the coefficient (1xe2x88x92k).
The image signal in which noise components are reduced by the noise reduction circuit 2008 is converted into a standard television (TV) signal by the encoder circuit 2009.
However, in the conventional image sensing apparatus shown in FIG. 1, a small coefficient k must be set in the noise reduction circuit to improve the noise reduction effect. However, when a subject that moves fast is sensed, the resolution lowers as the coefficient k decreases. Since the video camera is normally used for sensing a moving subject, the coefficient k must be set at a numerical value close to 1 in consideration of the resolution. As a result, since the noise reduction effect is impaired, noise components become conspicuous when a still subject such as a film or the like is sensed via the film adapter. This is the fourth problem.
As described above, the conventional image sensing apparatus that can mount the film adapter has room for improvement in automatic detection of attachment of the adapter.
Furthermore, if attachment of the adapter can be detected, there is room for improvement in automatically setting the image sensing apparatus in an optimal image sensing condition when the film adapter is attached.
It is an object of the present invention to provide an image sensing apparatus which automatically selects a film image sensing mode when a film adapter is attached, can remove and solve the above-mentioned drawbacks and problems, has good operability, and can assure reliable operations.
In order to achieve the above object, an image sensing apparatus of the present invention, which has a moving image sensing mode and a still image sensing mode, and can sense a close subject, comprises image sensing means for outputting a first image signal by photoelectrically converting a subject image, detection means for detecting based on a predetermined signal component in the first image signal if a subject is close to the apparatus (for example, processing for determining if a color difference signal falls within a range 201 to be described later), and control means for switching the image sensing mode to the still image sensing mode when the detection means detects that the subject is close to the apparatus.
Therefore, when a negative film is subjected to image sensing using a video camera, a negative/positive reversing function of the video camera can be automatically enabled, and the video camera can be automatically set in the still image sensing mode, thus eliminating cumbersome operations and avoiding unnecessary scenes from being sensed in the moving image sensing mode due to operation errors.
According to one preferred aspect of the present invention, the detection means detects based on chrominance signal components in the first image signal if the subject is a negative film. Whether or not the subject is a negative film is detected based on chrominance signal components in a sensed image signal, and when a negative film is detected, luminance and chrominance signal components are converted into those for a positive image, and the converted signal components are output. In case of a video camera, a characteristic color difference vector of a negative film is detected using a white balance circuit as a technique unique to video cameras so as to automatically set the apparatus in the film image sensing mode and to automatically enable the negative/positive reversing function. Hence, the operator is relieved from any troublesome operations for manually setting the apparatus in the positive/negative reversing mode and the still image sensing mode, and any probability of operation errors.
According to one preferred aspect of the present invention, the apparatus comprises first luminance component generation means (corresponding to a YC signal generation circuit 502 in embodiments) for generating a luminance component based on the first image signal, first chrominance component generation means (corresponding to color difference generation circuits 505 and 1101 in the embodiments) for generating chrominance components based on the first image signal, second luminance component generation means (corresponding to a negative/positive reversing circuit 513 in the embodiments) for generating a luminance component by reversing light and dark portions in correspondence with a luminance level of the first image signal, and second chrominance component generation means (corresponding to the negative/positive reversing circuit 513 in the embodiments) for generating chrominance components in accordance with the chrominance components of the first image signal using a predetermined conversion scheme, and when the detection means detects that the subject is not a negative film, the control means controls to generate an image signal using output signals from the first luminance component generation means and first chrominance component generation means, and when the detection means detects that the subject is a negative film, the control means controls to generate an image signal using output signals from the second luminance component generation means and second chrominance component generation means (corresponding to processing for selecting one of a film image sensing mode and moving image sensing mode depending on whether or not a color difference signal falls within the range 201 in FIG. 12 in the processing of the flow chart shown in FIG. 13).
According to one preferred aspect of the present invention, a film adapter for holding a subject such as a film can be detachably attached to a predetermined position of a front portion of an image sensing optical system, and the film image sensing mode is enabled by attaching the film adapter. Therefore, since the film image sensing mode is enabled by attaching the film adapter, film image sensing can be easily done by a normal video camera without specially modifying the camera itself.
It is another object of the present invention to provide an image sensing apparatus comprising image sensing means for outputting a first image signal by photoelectrically converting an optical image formed via an image sensing optical system, signal processing means (corresponding to a camera signal processing circuit 409 in an embodiment) for generating an image signal by performing predetermined processing of the first image signal, and film image sensing means for sensing a film image by mounting a film image sensing adapter, the signal processing means comprising first luminance component generation means (corresponding to a YC signal generation circuit 502 in the embodiments) for generating a luminance component of the image signal in accordance with a luminance level of the first image signal, first chrominance component generation means (corresponding to the color difference generation circuits 505 and 1101 in the embodiments) for generating chrominance components of the image signal in accordance with chrominance components of the first image signal, second luminance component generation means (corresponding to a negative/positive reversing circuit 513 in the embodiments) for generating a luminance component of the image signal by reversing light and dark portions in accordance with a luminance level of the first image signal, second chrominance component generation means (corresponding to the negative/positive reversing circuit 513 in the embodiments) for generating chrominance components of the image signal in accordance with chrominance components of the first image signal using a predetermined conversion scheme, and control means (corresponding to processing in the flow chart of FIG. 13 by a camera control circuit 105) which can select one of a moving image sensing mode for sensing a moving image, and a film image sensing mode for sensing a photographic film image using the film image sensing means, and selects the film image sensing mode when an image signal is generated using output signals from the second luminance component generation means and second chrominance component generation means. Hence, when a video camera senses a negative film as a still image using a film adapter or the like, the video camera can be automatically set in the still image sensing mode upon enabling the negative/positive reversing function of the video camera. In this manner, the operator is relieved of any troublesome operations for manually setting the apparatus in the positive/negative reversing mode and the still image sensing mode, and can avoid unnecessary scenes from being sensed in the moving image mode set as a result of operation errors.
According to one preferred aspect of the present invention, the apparatus comprises color identification means (corresponding to processing executed by the camera control circuit 105 in the embodiments) for identifying a color of the subject on the basis of information associated with a color of the first image signal, and the control means selects on the basis of an identification result of the color identification means whether the image signal is generated by the first luminance component generation means and first chrominance component generation means, or by the second luminance component generation means and second chrominance component generation means, and selects the film image sensing mode upon selecting image signal generation using the second luminance component generation means and second chrominance component generation means. Hence, the characteristic color difference vector of a negative film is detected using a white balance circuit as a technique unique to video cameras, so that the apparatus can be automatically set in the film image sensing mode, and can automatically enable the negative/positive reversing function. In this manner, the operator can be relieved of any burdensome operations for setting the apparatus in-the still image sensing mode after he or she sets the negative/positive reversing mode, and any probability of operation errors.
According to one preferred aspect of the present invention, the second luminance component generation means and second chrominance component generation means output a negative-to-positive reversed image signal.
It is still another object of the present invention to provide an image sensing apparatus comprising an image sensing optical system (corresponding to an inner focus lens shown in FIG. 6) which changes a position of a lens in correspondence with a subject distance, position detection means (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 shown in FIG. 5 in an embodiment) for detecting the position of the lens, image sensing means (corresponding to an image sensing element 407 in the embodiments) for outputting a first image signal by photoelectrically converting an optical image of a subject imaged via the image sensing optical system, and control means (mainly corresponding to processing in the flow chart of FIG. 14 by a camera control circuit 105 in the embodiments) which can select one of a plurality of image sensing modes including a moving image sensing mode for sensing a moving image and a film image sensing mode for sensing a close subject such as a film, and sets an image sensing mode in the film image sensing mode when the lens is located at a predetermined position. Hence, since the film image sensing mode is set in correspondence with the lens position, the film image sensing state using the film adapter can be accurately detected by detecting a specific lens position obtained from a closest distance in-focus condition of an image sensing lens. In this manner, the above-mentioned drawbacks can be removed and demerits of the prior art can be compensated for while preventing operation errors of the apparatus.
According to one preferred aspect of the present invention, the control means sets the film image sensing mode when the lens is located within a predetermined range on the closest distance side.
According to one preferred aspect of the present invention, the image sensing optical system comprises a magnification lens, and the control means (mainly corresponding to the camera control circuit 105 in the embodiments) sets the film image sensing mode when the magnification lens is located at a predetermined position on the wide-angle side, and the lens is located within a predetermined range on the closest distance side.
According to one preferred aspect of the present invention, a film adapter for holding a subject such as a film can be detachably attached to a predetermined position of a front portion of the image sensing optical system, and the film image sensing mode is enabled by attaching the film adapter. Therefore, since the film image sensing mode is enabled by attaching the film adapter, film image sensing can be easily done by a normal video camera without specially modifying the camera itself.
It is still another object of the present invention to provide an image sensing apparatus comprising an image sensing optical system (corresponding to an inner focus lens shown in FIG. 6) which changes a position of a lens in correspondence with a subject distance, position detection means (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 shown in FIG. 5 in an embodiment) for detecting the position of the lens, image sensing means (corresponding to an image sensing element 407 in the embodiments) for outputting a first image signal by photoelectrically converting an optical image of a subject imaged via the image sensing optical system, and control means (mainly corresponding to processing in the flow chart of FIG. 14 by a camera control circuit 105 in the embodiments) which can select one of a plurality of image sensing modes including a moving image sensing mode for sensing a moving image and a still image sensing mode for sensing a still image, and sets an image sensing mode in the still image sensing mode when the lens is located at a predetermined position (corresponding to a region 904 in FIG. 7 in the embodiments). More specifically, since the still image sensing mode is set depending on the lens position, the still image sensing mode that assumes film image sensing can be set detecting a specific lens position obtained from a closest distance in-focus condition of an image sensing lens. Thus, the above-mentioned drawbacks can be removed and demerits of the prior art can be compensated for while accurately detecting the film image sensing state and preventing operation errors of the apparatus.
According to one preferred aspect of the present invention, the control means sets the still image sensing mode when the lens is located with a predetermined range on the closest distance side (corresponding to the region 904 in FIG. 7 in the embodiments).
According to one preferred aspect of the present invention, the image sensing optical system comprises a magnification lens, and the control means sets the still image sensing mode when the magnification lens is located at a predetermined position on the wide-angle side (corresponding to a region 904 in FIG. 7 in the embodiments), and the lens is located within the predetermined range on the closest distance side.
According to one preferred aspect of the present invention, a film adapter (corresponding to a film adapter 3 in the embodiments) for holding a subject such as a film can be detachably attached to a predetermined position of a front portion of the image sensing optical system, and film image sensing is allowed in the still image sensing mode by attaching the film adapter. Therefore, since film image sensing is allowed by attaching the film adapter, film image sensing can be easily done by a normal video camera without specially modifying the camera itself.
It is still another object of the present invention to provide an image sensing apparatus comprising an image sensing optical system (corresponding to an inner focus lens shown in FIG. 6) which changes a position of a lens in correspondence with a subject distance, position detection means (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 shown in FIG. 5 in an embodiment) for detecting the position of the lens, image sensing means for outputting a first image signal by photoelectrically converting an optical image of a subject imaged via the image sensing optical system, signal processing means (corresponding to a camera signal processing circuit 409 in the embodiments) for generating an image signal on the basis of the first image signal, the signal processing means comprising first luminance component generation means (corresponding to a YC signal generation circuit 502 in the embodiments) for generating a luminance component of the image signal in accordance with a luminance component of the first image signal, first chrominance component generation means (corresponding to the color difference generation circuits 505 and 1101 in the embodiments) for generating chrominance components of the image signal in accordance with chrominance components of the first image signal, second luminance component generation means (corresponding to a negative/positive reversing circuit 513 in the embodiments) for generating a luminance component of the image signal by reversing light and dark portions in accordance with a luminance level of the first image signal, and second chrominance component generation means (corresponding to the negative/positive reversing circuit 513 in the embodiments) for generating chrominance components of the image signal in accordance with chrominance components of the first image signal using a predetermined conversion scheme, and control means (corresponding to processing in the flow chart of FIG. 15 by a camera control circuit 105 in the embodiments) which can select one of a moving image sensing mode for sensing an image of a normal subject and a film image sensing mode which allows to sense a film image, and switches an image sensing mode to the film image sensing mode when the lens is located at a predetermined position, and an image signal is generated using output signals from the second luminance component generation means and second chrominance component generation means. More specifically, since the image sensing mode is switched to the film image sensing mode in correspondence with the lens position, the film image sensing mode that assumes film image sensing can be set by detecting a specific lens position obtained from the closest distance in-focus condition of an image sensing lens. Thus, the above-mentioned drawbacks can be removed and demerits of the prior art can be compensated for while accurately detecting the film image sensing state and preventing operation errors of the apparatus. Since the specific position obtained from the closest distance in-focus condition of an image sensing lens is detected as well as the characteristic color difference vector of a negative film, the above-mentioned drawbacks can be removed and demerits of the prior art can be compensated for while accurately detecting the negative film image sensing state and preventing operation errors of the apparatus.
According to one preferred aspect of the present invention, the image signal generated using the output signals from the second luminance component generation means and second chrominance component generation means is a negative-to-positive reversed image signal, and the film image sensing mode is set to convert an image on a negative film into a positive image, and to output the positive image.
According to one preferred aspect of the present invention, a film adapter (corresponding to a film adapter 3 in the embodiments) for holding a subject such as a film can be detachably attached to a predetermined position of a front portion of the image sensing optical system, and the film image sensing mode is allowed by attaching the film adapter. Therefore, since film image sensing is allowed by attaching the film adapter, film image sensing can be easily done by a normal video camera without specially modifying the camera itself.
According to one preferred aspect of the present invention, the image sensing optical system comprises a magnification lens, and the control means sets the film image sensing mode when the magnification lens is located at a predetermined position on the wide-angle side, and the lens is located within a predetermined range on the closest distance side. Hence, when the magnification lens is located at the predetermined position on the wide-angle side and the lens is located within the predetermined range on the closest distance side, the film image sensing mode is set, thus realizing a system which utilizes the characteristics of the inner focus lens and has good operability.
It is still another object of the present invention to provide an image sensing apparatus which can select one of a moving image sensing mode and still image sensing mode, and can sense an image of a close subject such as a film, comprising image sensing means (corresponding to an image sensing element 407 in an embodiment) for outputting a first image signal by photoelectrically converting a subject image formed via an image sensing optical system, and control means (corresponding to processing in the flow chart of FIG. 16 by a camera control circuit 105 in the embodiments) for switching an image sensing mode to the still image sensing mode in accordance with user operation for sensing an image of the close subject such as the film.
Accordingly, since the image sensing mode is switched to the still image sensing mode in accordance with user operation for film image sensing, when a negative film image is sensed as a still image using a video camera, the video camera can be automatically set in the still image sensing mode by enabling, e.g., a negative/positive reversing function of the video camera. Hence, cumbersome operations can be alleviated, and unnecessary scenes can be prevented from being sensed in the moving image mode set due to operation errors.
It is still another object of the present invention to provide an image sensing apparatus comprising image sensing means (corresponding to an image sensing element 407 in an embodiment) for outputting a sensed image signal by photoelectrically converting a subject image formed via an image sensing optical system, and signal processing means (corresponding to a camera signal processing circuit in the embodiments) for generating a video signal by performing predetermined processing of the sensed image signal, the signal processing means comprising first luminance component generation means (corresponding to a YC signal generation circuit 502 or 1103 in an embodiment) for generating a luminance component of the video signal in accordance with a luminance level of the sensed image signal, first chrominance component generation means (corresponding to a color difference signal generation circuit 505 or 1101 in the embodiments) for generating chrominance components of the video signal in accordance with chrominance components of the sensed image signal, second luminance component generation means (corresponding to a negative/positive reversing circuit 512 or 1601 in the embodiments) for generating a luminance component of the video signal by reversing light and dark portions in accordance with the luminance level of the sensed image signal, second chrominance component generation means (corresponding to the negative/positive reversing circuit 512 or 1601 in the embodiments) for generating chrominance components of the video signal in accordance with the chrominance components of the sensed image signal using a predetermined conversion scheme, color identification means for identifying a color of the subject on the basis of information associated with a color in the sensed image signal, and selection means (corresponding to a camera control circuit 105, 902, 1102, 120, or 1401 in the embodiments) for selecting the first luminance component generation means and chrominance component generation means, or the second luminance component generation means and chrominance component generation means, that are to be used upon generating and outputting a video signal, in accordance with an identification result of the color identification means.
Hence, signal processing optimal to the state of the subject to be sensed can be automatically done in accordance with signal components in the sensed image signal.
It is still another object of the present invention to provide an image sensing apparatus comprising image sensing means for outputting a sensed image signal by photoelectrically converting a subject image formed via an image sensing optical system, and signal processing means for generating a video signal by performing predetermined processing of the sensed image signal, the signal processing means comprising first luminance component generation means for generating a luminance component of the video signal in accordance with a luminance level of the sensed image signal, first chrominance component generation means for generating chrominance components of the video signal in accordance with chrominance components of the sensed image signal, second luminance component generation means for generating a luminance component of the video signal by reversing light and dark portions in accordance with the luminance level of the sensed image signal, second chrominance component generation means for generating chrominance-components of the video signal in accordance with the chrominance components of the sensed image signal using a predetermined conversion scheme, color identification means for identifying a color of the subject on the basis of information associated with a color in the sensed image signal, first selection means for selecting the first luminance component generation means and chrominance component generation means, or the second luminance component generation means and chrominance component generation means, that are to be used upon generating and outputting a video signal, in accordance with an identification result of the color identification means, and second selection means (corresponding to a camera control circuit 902 in an embodiment) for inhibiting operation of the first selection means. Accordingly, signal processing optimal to the state of the subject to be sensed can be automatically done in accordance with signal components in the sensed image signal, and operation errors of that automatic selection function can be prevented, thus preferentially reflecting the photographer""s will.
According to one preferred aspect of the present invention, the image sensing apparatus comprises third selection means (corresponding to the camera control circuit 902 in the embodiments) for, when the second selection means inhibits operation of the first selection means, selecting the first luminance component generation means and chrominance component generation means, or the second luminance component generation means and chrominance component generation means, that are to be used upon generating and outputting a video signal, independently of the first selection means.
According to one preferred aspect of the present invention, the image sensing apparatus comprises white balance adjustment means (corresponding to gain control circuits 503 and 504, and a camera control circuit 105, 902, 1102, 120, or 1401 in the embodiments) for generating color difference signals based on outputs from the first luminance component generation means and the first chrominance component generation means, and adjusting white balance by controlling gains of the color difference signals. Accordingly, negative film image sensing can be automatically detected, and a negative/positive reversing function is automatically executed by detecting, e.g., the characteristic color difference vector of a negative film using a white balance circuit as a technique unique to the video camera. When a negative film image is to be sensed using a film adapter or the like, the operator is free from any cumbersome operations for enabling the reversing function by operating a switch without arranging any film adapter mounting detection switch to the video camera. Also, since the means for disabling the automatic execution function of the negative/positive reversing function based on negative film detection is arranged, operation errors of the negative/positive reversing function caused by detection errors of a negative film, which tend to take place when a subject having a hue similar to the negative film is sensed, can be prevented.
According to one preferred aspect of the present invention, there is disclosed the image sensing apparatus wherein the second luminance component generation means and the second chrominance component generation means output a negative-to-positive reversed video signal.
According to one preferred aspect of the present invention, the image sensing apparatus comprises an image sensing optical system, and a film image sensing adapter (corresponding to a film adapter 803 in the embodiments) for holding a film at a predetermined position on a front surface of the image sensing optical system. Accordingly, a film image sensing apparatus which can execute film image sensing by attaching the film image sensing adapter to the image sensing optical system, can use the existing camera itself, does not require any bulky arrangement, allows a size reduction, simple operation, and cost reduction, and has good operability, can be realized.
According to one preferred aspect of the present invention, the color identification means determines a negative film on the basis of color difference signals generated based on the sensed image signal. Since a negative film is determined based on the color difference signals, R, G, and B signals, and the like generated based on the sensed image signal, selection by the selection means can be done in correspondence with the circuit arrangement of the video camera, and the degree of freedom in design can be increased.
According to one preferred aspect of the present invention, the color identification means determines a negative film on the basis of R, G, and B signals generated based on the sensed image signal.
According to one preferred aspect of the present invention, the color identification means determines a negative film on the basis of outputs from the first luminance component generation means and first chrominance component generation means.
According to one preferred aspect of the present invention, the color identification means determines a negative film on the basis of outputs from the second luminance component generation means and second chrominance component generation means. Hence, since a negative film can be determined on the basis of signals either before or after negative/positive reversing, means with higher reliability can be selected in accordance with situations and the circuit arrangement of the video camera, thus increasing the degree of freedom in design, and improving the reliability of negative film identification.
It is still another object of the present invention to provide an image sensing apparatus, which can select one of a moving image sensing mode and still image sensing mode, comprising image sensing means (corresponding to an image sensing element 407 in an embodiment) for outputting a sensed image signal by photoelectrically converting a subject image formed via an image sensing optical system (corresponding to lenses 402, 403, 405, and 406, and an iris 404 in the embodiments), first luminance component generation means (corresponding to a YC signal generation circuit 502 in the embodiments) for generating a luminance signal component on the basis of the sensed image signal, first chrominance component generation means (corresponding to the color difference generation circuits 505, 1101 in the embodiments) for generating chrominance signal components on the basis of the sensed image signal, second luminance component generation means (corresponding to a negative/positive reversing circuit 513 in the embodiments) for generating a luminance component by reversing light and dark portions in correspondence with a luminance level of the sensed image signal, second chrominance component generation means (corresponding to the negative/positive reversing circuit 513 in the embodiments) for generating chrominance components in accordance with chrominance components of the sensed image signal using a predetermined conversion scheme, and control means which can select one of the moving image sensing mode and the still image sensing mode, and selects the still image sensing mode when a video signal is generated using output signals from the second luminance component generation means and second chrominance component generation means (corresponding to processing for selecting one of a film image sensing mode and moving image sensing mode depending on whether or not a color difference signal falls within a range in the processing of the flow chart shown in FIG. 3 executed by a camera control circuit 105 in the embodiments). Hence, the image sensing mode can be automatically set in correspondence with the state of the signal processing circuit, thus effectively preventing operation errors and improving operability.
For example, when a negative film image is sensed using a video camera, the video camera can be automatically set in the still image sensing mode by enabling its negative/positive reversing function. Hence, complicated operations can be precluded, and unnecessary scenes can be prevented from being sensed in the moving image mode set by operation errors.
According to one preferred aspect of the present invention, the image sensing apparatus comprises color identification means (corresponding to processing in steps A302 and A303 in the flow chart corresponding to the processing executed by the camera control circuit 105 in the embodiments) for identifying a color of the subject in accordance with the chrominance component in the sensed image signal, and the control means selects the first luminance component generation means and first chrominance component generation means or the second luminance component generation means and second chrominance component generation means, that are to be used upon generating the video signal, in accordance with an output from the color identification means, and selects the still image sensing mode when the video signal is generated using the output signals from the second luminance component generation means and second chrominance component generation means. As described above, since the luminance and chrominance signal processing circuits are automatically switched on the basis of chrominance signal components in the sensed image signal, for example, when the subject is a negative film, luminance and chrominance signal components are converted to those for a positive image, and the image sensing mode can also be switched to the still image sensing mode suitable for film image sensing.
According to one preferred aspect of the present invention, the image sensing apparatus comprises an image sensing optical system which changes a position of a lens in correspondence with a subject distance, and position detection means (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 in the embodiments) for detecting the position of the lens, and the control means forcibly selects the still image sensing mode when the position detection means detects that the lens is located at a predetermined position, and the video signal is to be generated using output signals from the second luminance component generation means and second chrominance component generation means. In this manner, since the lens position information is used for setting the image sensing mode, the film image sensing mode (still image sensing mode) can be automatically set with high precision.
It is still another object of the present invention to provide an image sensing apparatus comprising image sensing means (corresponding to an image sensing element 407 in an embodiment) for outputting a sensed image signal by photoelectrically converting an optical image formed via an image sensing optical system, first luminance component generation means (corresponding to a YC signal generation circuit 502 in the embodiments) for generating a luminance component of a video signal in accordance with a luminance level of the sensed image signal, first chrominance component generation means (corresponding to the color difference generation circuits 505, 1101 in the embodiments) for generating chrominance components of the video signal in accordance with chrominance components of the sensed image signal, second luminance component generation means (corresponding to a negative/positive reversing circuit 513 in the embodiments) for generating a luminance component of the video signal by reversing light and dark portions in accordance with a luminance level of the sensed image signal, second chrominance component generation means (corresponding to the negative/positive reversing circuit 513 in the embodiments) for generating chrominance components of the video signal in accordance with chrominance components of the sensed image signal using a predetermined conversion scheme, and control means which can select one of a still image single shot mode for sensing a single still image, and a still image sequential shot mode for sequentially sensing the still images, and inhibits the still image sequential shot mode when the video signal is generated using output signals from the second luminance component generation means and second chrominance component generation means (corresponding to processing in the flow chart shown in FIG. 36 in the embodiments). In the image sensing apparatus which has a single shot mode and sequential shot mode in association with still image sensing, and has a plurality of sets of luminance signal generation means and chrominance signal generation means, switching and inhibition of the still image single shot mode and still image sequential shot mode are automatically controlled in correspondence with the luminance signal generation means and chrominance signal generation means to be used at that time. Accordingly, the image sensing mode can be automatically set in correspondence with the state of the signal processing circuit, thus effectively preventing operation errors and improving operability.
For example, when a negative film image is sensed using a video camera, the sequential shot mode is inhibited from being set as the still image sensing mode and the single shot mode can be automatically set by enabling the negative/positive reversing function of that video camera. In this way, wasteful operations such as sequential shots of an identical film image can be prevented, and the video camera can be automatically set. Hence, complicated operations can be done away with and unnecessary scenes can be prevented from being sensed in the moving image mode set by operation errors.
According to one preferred aspect of the present invention, the image sensing apparatus comprises color identification means (corresponding to processing in steps 1702 and 1703 in the flow chart shown in FIG. 36 corresponding to the processing executed by a camera control circuit 105 in the embodiments) for identifying a color of the subject in accordance with the chrominance component in the sensed image signal, and the control means selects the first luminance component generation means and first chrominance component generation means or the second luminance component generation means and second chrominance component generation means, that are to be used upon generating the video signal, in accordance with an output from the color identification means, and selects the still image single shot mode and inhibits selection of the still image sequential shot mode when the video signal is generated using the output signals from the second luminance component generation means and second chrominance component generation means. As described above, since the luminance and chrominance signal processing circuits are automatically switched on the basis of chrominance signal components in the sensed image signal, for example, when the subject is a negative film, luminance and chrominance signal components are converted to those for a positive image, and the image sensing mode can also be switched to the still image single shot mode suitable for film image sensing.
For example, the characteristic color difference vector of a negative film is detected using a white balance circuit as a technique unique to video cameras so as to automatically set the apparatus in the film image sensing mode and to automatically enable the negative/positive reversing function. Hence, the operator is relieved from any troublesome operations for manually setting the apparatus in the positive/negative reversing mode and the still image sensing mode, and any probability of operation errors.
According to one preferred aspect of the present invention, the image sensing apparatus comprises an image sensing optical system (corresponding to lenses 402, 403, 405, and 406, and an iris 404 in the embodiments) which changes a position of a lens in correspondence with a subject distance, and position detection means (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 in the embodiments) for detecting the position of the lens, and the control means forcibly selects the still image single shot mode and inhibits selection of the still image sequential mode when the position detection means detects that the lens is located at a predetermined position, and the video signal is to be generated using output signals from the second luminance component generation means and second chrominance component generation means. In this fashion, since the lens position information is also used for setting the image sensing mode, the film image sensing mode (still image single shot mode) can be automatically set with higher precision.
It is still another object of the present invention to provide an image sensing apparatus comprising image sensing means (corresponding to an image sensing element 407 in an embodiment) for outputting a sensed image signal by photoelectrically converting an optical image formed via an image sensing optical system (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 in the embodiments), negative/positive reversing means (corresponding to a negative/positive reversing circuit 513 in the embodiments) for reversing a negative image to a positive image by performing predetermined processing of luminance and chrominance signals, and control means which can select one of a still image single shot mode for sensing a single still image, and a still image sequential shot mode for sequentially sensing the still images, and inhibits the still image sequential shot mode upon operation of the negative/positive reversing means (corresponding to processing in the flow charts shown in FIGS. 36 and 37 by a camera control circuit in the embodiments). In this manner, since selection of the still image sequential shot mode is inhibited upon negative/positive reversing, the operator is exempt from cumbersome operations for setting a negative/positive reversing mode and then switching apparatus to the still image single shot mode, and possibility of operation errors.
According to one preferred aspect of the present invention, the image sensing apparatus comprises color identification means (corresponding to processing in steps 1702 and 1703 in the flow chart shown in FIG. 36 corresponding to the processing executed by a camera control circuit 105 in the embodiments) for detecting based on chrominance components in the sensed image signal if a negative film is subjected to image sensing, and the control means enables the negative/positive reversing means to perform negative/positive reversing, selects the still image single shot mode, and inhibits selection of the still image sequential shot mode when the color identification means detects that the negative film is subjected to image sensing. In this manner, since it is automatically detected that the negative film is subjected to image sensing, operations for performing negative/positive reversing by enabling the negative/positive reversing means, selecting the still image single shot mode, and inhibiting selection of the still image sequential shot mode can be automated.
According to one preferred aspect of the present invention, the image sensing apparatus comprises an image sensing optical system (corresponding to lenses 402, 403, 405, and 406, and an iris 404 in the embodiments) which changes a position of a lens in correspondence with a subject distance, and position detection means (corresponding to processing for counting driving pulses to be supplied to a magnification lens driver 413 and focus-compensation lens driver 415 in a lens/camera control circuit 418 in the embodiments) for detecting the position of the lens, and the control means enables the negative/positive reversing means to perform negative/positive reversing, selects the still image single shot mode, and inhibits selection of the still image sequential shot mode when the position detection means detects that the lens is located at a predetermined position, and the color identification means detects that the negative film is subjected to image sensing. In this manner, since the lens position information is also used for setting the image sensing mode, the film image sensing mode (still image single shot mode) can be automatically set with higher precision.
It is still another object of the present invention to provide an image sensing apparatus which has a normal image sensing mode and a film image sensing mode for sensing a film image or the like, comprising image sensing means (corresponding to an image sensing element 2006), exposure control means (corresponding to a gate circuit 2011, an integrator 2012, an exposure control circuit in a system control circuit 2013, a D/A converter 2016, an iris driving circuit 2017, an iris motor 2019, an iris 2005, and an iris encoder 2015 in FIG. 39) for making exposure control by extracting a predetermined signal component from a sensed image signal output from the image sensing means, and control means (corresponding to a reset pulse generator in the system control circuit 2013 in FIG. 39) for changing response characteristics of the exposure control means in correspondence with the normal image sensing mode and the film image sensing mode. In this manner, since the response characteristics of the exposure control means are changed between the normal image sensing mode and the film image sensing mode, an optimal image sensing state can be obtained in each image sensing mode.
According to one preferred aspect of the present invention, there is provided the image sensing apparatus wherein the predetermined signal component is a luminance signal level, the exposure control means comprises an integrator for integrating the luminance signal level during a predetermined period, and the control means sets a large integral time constant of the integrator when the film image sensing mode is selected. As described above, since the integrator for integrating the luminance levels during the predetermined period is arranged as the exposure control means, and a large integral time constant is set upon selecting the film image sensing mode, even when the exposure state largely changes upon feeding the frame of a film, image quality can be prevented from deteriorating, and the exposure state can be quickly set after the film frame has moved.
It is still another object of the present invention to provide an image sensing apparatus comprising film image sensing mode selection means for notifying a film image sensing mode, and signal processing system switching means for switching a setup state of a signal processing system to a setup state for film image sensing in the film image sensing mode, wherein when the film image sensing mode selection means detects the film image sensing mode, the signal processing system switching means switches the setup state of the signal processing system to the setup state for film image sensing, thereby switching a reference voltage of an A/D converter for A/D-converting a sensed image signal to different voltages in correspondence with the film image sensing mode and a normal image sensing mode to improve an S/N ratio in the film image sensing mode.
With this arrangement, since the signal processing system switching means switches the signal processing system to the setup state for the film image sensing mode in the film image sensing mode, the S/N ratio of an image signal obtained by sensing a film can be improved. Furthermore, with this arrangement, in the film image sensing mode, the top-side reference voltage of the A/D converter can be switched to a voltage optimal to film image sensing. Moreover, the S/N ratio in the film image sensing mode for a negative film, positive film, and the like can be improved without any influences on image quality in the normal image sensing mode, and a higher-quality image can be provided.
According to one preferred aspect of the present invention, the image sensing apparatus of claim 1 is characterized in that a top-side reference voltage of the A/D converter is set to narrow a dynamic range in the film image sensing mode than in the normal image sensing mode.
With this arrangement, the dynamic range of the A/D converter is narrowed in the film image sensing mode, thus processing an/image signal in an optimal state to film image sensing.
According to one preferred aspect of the present invention, the film image sensing mode selection means comprises means for detecting switching between the film image sensing mode and normal image sensing mode.
With this arrangement, the top-side reference voltage of the A/D converter can be switched by detecting the film image sensing mode or normal image sensing mode.
In order to achieve the above objects, an image sensing apparatus according to the present invention, which has a function of sensing a photographic film image, comprises detection means for detecting attachment of an adapter used for sensing a photographic film image, and a noise reduction circuit, and a noise reduction amount of the noise reduction circuit is switched in synchronism with the attachment of the adapter detected by the detection means.
According to one preferred aspect of the present invention, the noise reduction circuit has a field memory or frame memory, and executes field or frame correlation noise reduction.
According to one preferred aspect of the present invention, the noise reduction circuit has a line memory, and executes line correlation noise reduction.
It is still another object of the present invention to provide an image sensing apparatus having a function of sensing a photographic film, comprising a reversing circuit for reversing a negative image on the photographic film to a positive image, and a noise reduction circuit, wherein a noise reduction amount of the noise reduction circuit is switched in synchronism with reversing by the reversing circuit.
According to one preferred aspect of the present invention, the noise reduction circuit has a field memory or frame memory, and executes field or frame correlation noise reduction.
According to one preferred aspect of the present invention, the noise reduction circuit has a line memory, and executes line correlation noise reduction.